var maxProfit = function (prices = []) {
  const n = prices.length
  const dp = new Array(n).fill(0).map(v => new Array(2).fill(0))
  dp[0][0] = 0, dp[0][1] = -prices[0]
  for (let i = 1; i < n; i++) {
    dp[i][0] = Math.max(dp[i - 1][0], dp[i - 1][1] + prices[i])
    dp[i][1] = Math.max(dp[i - 1][1], dp[i - 1][0] - prices[i])
  }
  console.log(dp);
  return dp[n-1][0]
}
console.log(maxProfit([7,1,5,3,6,4]));